List of top Questions asked in JEE Main- 2014

Which of the following is not formed when \(\mathrm{H_2S}\) reacts with acidic \(\mathrm{K_2Cr_2O_7}\) solution ?

A compound of vanadium chloride has spin only magnetic moment of 1.73 BM. Its formula is

The correct statement about the magnetic properties of \([\mathrm{Fe(CN)_6}]^{3-}\) and \([\mathrm{FeF_6}]^{3-}\) is : (Z = 26).

In which of the following pairs A is more stable than B?

The standard enthalpy of formation of \(\mathrm{NH_3}\) is \(-46.0\ \mathrm{kJ/mol}\). If bond enthalpy of \(\mathrm{H_2}\) is \(-436\ \mathrm{kJ/mol}\) and that of \(\mathrm{N_2}\) is \(-712\ \mathrm{kJ/mol}\), the average bond enthalpy of \(\mathrm{N-H}\) bond in \(\mathrm{NH_3}\) is :

The half-life period of a first-order reaction is 15 minutes. The amount of substance left after one hour will be

A current of 10.0 A flows for 2.00 h through an electrolytic cell containing a molten salt of metal X. This results in the decomposition of 0.250 mol of metal X at the cathode. The oxidation state of X in the molten salt is :
(F = 96,500 C)

The standard electrode potentials \(\left(E^{\circ}_{M^+/M}\right)\) of four metals A, B, C and D are \(-1.2\ \mathrm{V}\), \(0.6\ \mathrm{V}\), \(0.85\ \mathrm{V}\) and \(-0.76\ \mathrm{V}\), respectively. The sequence of deposition of metals on applying potential is

The temperature at which oxygen molecules have the same root mean square speed as helium atoms have at 300 K is : (Atomic masses : He = 4 u, O = 16 u)

Which of the following has unpaired electron(s)?

In the following sets of reactants which two sets best exhibit the amphoteric character of \(\mathrm{Al_2O_3\cdot xH_2O}\) ?
Set I: \(\mathrm{Al_2O_3\cdot xH_2O_{(s)}+OH^-_{(aq)}}\)
Set II: \(\mathrm{Al_2O_3\cdot xH_2O_{(s)}+H_2O_{(l)}}\)
Set III: \(\mathrm{Al_2O_3\cdot xH_2O_{(s)}+H^+_{(aq)}}\)
Set IV: \(\mathrm{Al_2O_3\cdot xH_2O_{(s)}+NH_{3(aq)}}\)

The number and type of bonds in \(\mathrm{C_2^{2-}}\) ion in \(\mathrm{CaC_2}\) are:

Identify the gate and match \(A, B, Y\) in the bracket to check.

Using monochromatic light of wavelength \(\lambda\), an experimentalist sets up the Young's double slit experiment in three ways as shown.

If she observes that \(y=\beta'\), the wavelength of light used is :

If the binding energy of the electron in a hydrogen atom is \(13.6\ \mathrm{eV}\), the energy required to remove the electron from the first excited state of \(\mathrm{Li^{++}}\) is :

The focal lengths of objective lens and eye lens of a Galilean Telescope are respectively \(30\ \mathrm{cm}\) and \(3.0\ \mathrm{cm}\). Telescope produces virtual, erect image of an object situated far away from it at least distance of distinct vision from the eye lens. In this condition the Magnifying Power of the Galilean Telescope should be :

For which of the following particles will it be most difficult to experimentally verify the de-Broglie relationship?

The mid points of two small magnetic dipoles of length \(d\) in end-on positions, are separated by a distance \(x\) (\(x \gg d\)). The magnitude of force between them is proportional to \(x^{-n}\) where \(n\) is :

The magnetic field of earth at the equator is approximately \(4\times10^{-5}\,\mathrm{T}\). The radius of earth is \(6.4\times10^{6}\,\mathrm{m}\). Then the dipole moment of the earth will be nearly of the order of :

Match List I (Wavelength range of electromagnetic spectrum) with List II (Method of production of these waves) and select the correct option from the options given below the lists.

List I	List II
(a) \(700\ \mathrm{nm}\) to \(1\ \mathrm{mm}\)	(i) Vibration of atoms and molecules.
(b) \(1\ \mathrm{nm}\) to \(400\ \mathrm{nm}\)	(ii) Inner shell electrons in atoms moving from one energy level to a lower level.
(c) \(\lt 10^{-3}\ \mathrm{nm}\)	(iii) Radioactive decay of the nucleus.
(d) \(1\ \mathrm{mm}\) to \(0.1\ \mathrm{m}\)	(iv) Magnetron valve.

A diver looking up through the water sees the outside world contained in a circular horizon. The refractive index of water is \(\frac{4}{3}\), and the diver's eyes are \(15\ \mathrm{cm}\) below the surface of the water. Then the radius of the circle is :

Three capacitances, each of \(3\ \mu\mathrm{F}\), are provided. These cannot be combined to provide the resultant capacitance of :

The magnitude of the average electric field normally present in the atmosphere just above the surface of the Earth is about 150 N/C, directed inward towards the center of the Earth. This gives the total net surface charge carried by the Earth to be : [Given : \(\epsilon_0 = 8.85\times10^{-12}\ \mathrm{C^2/N\text{-}m^2}\), \(R_E = 6.37\times10^{6}\) m]

Two bodies of masses 1 kg and 4 kg are connected to a vertical spring, as shown in the figure. The smaller mass executes simple harmonic motion of angular frequency 25 rad s\(^{-1}\), and amplitude 1.6 cm while the bigger mass remains stationary on the ground. The maximum force exerted by the system on the floor is (take \(g = 10\ \mathrm{m\,s^{-2}}\)).

A particle which is simultaneously subjected to two perpendicular simple harmonic motions represented by; \(x = a_1\cos\omega t\) and \(y = a_2\cos 2\omega t\) traces a curve given by :